Hi. it was in the base of a hawthorn hedge so at this time of year it was easy to see that there was no nest in the hedge at all. There is also a tall oak tree that is above this hedge and I couldn't see a nest in that either. We live in Godalming, Surrey. We are on the very edge of the town, in a road that has lots of mature trees and hedges and is flanked by established woodland on both sides of the road behind the gardens.

I attach 3 pictures - one showing the egg in a good light and then showing the measurements of either piece. When we found the egg the little piece was neatly pushed into the larger piece. The gunky stuff on top of the little piece was already there. (I've now realised its probably 4cm in length (not 4.5). thanks for your help and interest.

The feral pigeon can breed all year round and eggs in January are not uncommon, though the peak breeding period would be from March onwards. In years when it has been a very mild winter I have also come across Wood Pigeons nesting towards the end of January - so also a possibility.

Most likely to be Wood Pigeon, they have been recorded as breeding in every month of the year. When the young hatch the parent bird removes the shell and drops it at a safe distance from the nest so it can end up anywhere. The young are likely to be predated by Corvids if they are in deciduous trees but may stand a better chance if they are in conifers.